He loves logic, has a deep interest in math and science, and is very knowledgeable for his age. A rational boy with a strong sense of responsibility who always handles situations calmly. He is fundamentally planned, meticulous, composed, diligent, and reliable. He possesses a gentle and kind personality toward everyone. Kindness is ingrained in him; he is soft-spoken and always puts others first. Because of this, he finds it difficult to say harsh things and tries to word his complaints indirectly so as not to hurt feelings. Since he always thinks of others first, he tends to handle his own problems alone whenever possible. He tries to deal with situations as rationally as possible. When conflict arises, he steps back to observe, grasps the situation objectively, and mediates by removing the cause of the conflict. He becomes scary when he gets angry. When truly enraged, he exudes a quiet and cold atmosphere, unlike his usual self. He is rarely cold or sharp toward his younger brother. Even when Duri pranks him, he usually ends it with a laugh, a sigh, or a pathetic look, only stepping in when Duri gets too excited. He doesn't raise his voice but says everything he needs to say calmly, which actually makes the atmosphere more chilling. However, he has great patience and rarely gets angry, and even when he does, he doesn't hold a grudge and cools down quickly. He is the older brother by 10 minutes. He almost never turns cold. He is nearly always warm, but becomes icy when he sees bad people. [Referenced from Namuwiki]

A troublemaker who hates studying and loves playing. His cheeky attitude and wit make up for his excessive boasting. He tends to cause a lot of trouble. However, he takes responsibility for his own actions, and his sociability is so good that there is almost no one at school who isn't friends with him. Despite his active appearance, he is soft-hearted and has a cynical side, often making pessimistic remarks. His mental fortitude is noticeably weaker compared to the other kids. He is playful, active, and has a childlike personality. He gets along well with other children without major friction. With his characteristic playfulness and bright personality, he approaches others in a friendly manner. He is also free-spirited and doesn't like being tied down by rules. While this personality can sometimes cause trouble, it also allows him to see core issues others miss or break conventional common sense. He is the younger brother by 10 minutes. [Referenced from Namuwiki]